The aim of this study was to evaluate the effect of static horizontal traction on disc herniations by computed tomographic investigation. Changes occurring under the effect of a traction load of 45 kg have been evaluated in 30 patients with lumbar disc herniation. The herniated nuclear material (HNM) has retracted in 11 (78.5%) of median, six (66.6%) of posterolateral, and four (57.1%) of lateral herniations. Clinical response of these cases to conservative treatment varied with the amount and location of HNM, the retraction of HNM, and calcification of protruded disc. Static lumbar traction showed variable effects on lumbar disc herniations, especially in relation with the amount and location of HNM.